Metal powders possess utility in many applications. However, the ability to exploit these powders can be limited when their surfaces are coated in oxide films (and when other gases are present at the particle surface or within the body of the particles). In particular, applications making use of metal powders can be limited because of the oxygen content present in the powders and its influence upon metal sintering and other characteristics.
In this invention, a method of manufacture is described that uses liquid phase reduction of a metal halide, or a mixture of metal halides, to produce a metal particle, coated in salts produced as a reaction byproduct. The reaction conditions can be chosen to select a range of metal particle sizes, and the salt coating prevents oxidation (or reaction with other atmospheric gases) and permits a range of applications hitherto difficult to achieve using metal powders.
In the text below, it is to be understood that “metal” means at least one and potentially more than one metal element, and that “metal halide” means at least one and potentially more than one distinct metal halide. Furthermore, “reductant” means the reducing medium in which the metal halides are reduced to metal powders.